Apparatus for making plywood



March 26, 1929. OSGQQD APPARATUS FOR MAKING PLYWOOD Filed Nov. 15, 1926 Zlwuemtor Patented Mar. 26, 1929.

'- UNITED STATES PATENT orrlca.

GEOIEGE HENRY OSGOOi), OF TACOMA, WASHINGTON.

' APPARATUS FOR MAKING PLYWOOD.

Application filed November 13, 1926. Serial No. 148,132.

This invention relates to methods and-apparatus for making plywood, and especially to the methods and apparatus used in pressing the freshly glued layers of veneer wood while the glue t ereof is drying.

The objects of the invention are, first, to provide means for receiving the raw plywood, comprising the several sheets ofveneer, assembled and suitably coated with glue on their inner surfaces, and feeding this raw plywood panel alone through a press whereby it is continuously moved therethrough and whereby, by t e time the ply- ,wood is delivered at the other end of the apparatus, the gluetherein has set and the panel of plywood is completely made and may then, at once, be trimmed or otherwise worked without any further delay; second, in which the pressure applied in such a press, through which the panel being made passes, increases progressively; third, in which the pressure is applied between a fixed body, or

series of bodies, and a complementary springs pressed body, or series of bodies, thereby causing every portion of each panel to pass through identical pressure conditions, since everypart thereo must pass between any and every such pair of pressure bodies; fourth, inwhich the initial compression of each spring may be independently adjusted whereby the pressure applied thereby, when the pressing body is 'raised a predetermined distance by the passing wood panel, is made uniform over a certain section of the apparatus; fifth, in which the pressure of all the springs, in any section of the apparatus, may be simultaneously adjusted, thereby permitting the pressure tobe progressively increased from one section to the next, and thereby permitting quick adjustment of the apparatus to accommodate a change in the trated in the accompanying drawings, wherein one form of the apparatus to carry out the improved method, is illustrated, in which Fig. 1 is a diagrammatic side elevation of such an apparatus; Fig. 2 is a side elevation of the ad acent ends of two contiguous sections thereof, on a larger scale; and Fig. 3 p

is a cross-section of a portion thereof.

Similar numerals of reference; refer to similar parts throughout theseveral views.

The art of making plywood panels has been substantially as follows :The sheets of veneer are passed through the glue spreader and are thenassembled into a raw panel of the desired arrangement. The raw panel thus formed is stacked with similar raw panels into a pile of several feet in height and,. if. the veneer is very thin, a sheet of paper is inserted between each such panel and the adjacent panels, Then this pile of raw panels is transferredlto ahydraulic, or other powerful, press and is compressed therein. While'it'is in this press it is clamped between pressure plates by suitable adjustable bars. Then the hydraulic pressure thereon is released and the pile, still under the pressurefrom the tension in said clamping bars, is transported and stored until the glue.

has had time to setj Under such condit on's it is evident that the glue used cannot be of a quick-drying character, because of the time "necessary to assemble the lar to make up the said pile, and therefore it requires a considerable time, after the panels have been put under pressure of the bydraulic press, before the glue has set therein e number of panels which-goi sufiiciently for the clamping bars and plates to be removed. It is also evident that this process requires a large number, of sets of clamping. plates and bars because the time that it takes the glue to set is much longer than the time'taken in assembling a pile of raw panels. Also this process requires a very large investment in storage space, in a large plant, and requires the labor of many ,men in the various steps of the process as above outlined. It further necessitates the gluing up of a large number of panels before any of them can have any adequate pressure applied thereto, and this results in a certain loss in quality of the gluing.

All these objects are removed by my improved process and in the apparatus ,whereby it is carried out. The floor space required i s-only that occupied by my continuous press,

and substantially no labor is used between the assemblingtable and the finished panel.

It reduces the capital tied up in panels in which the glue is setting because each panel is ready for trimming, or otherwise being worked on, in'about four minutes after it has been assembled. It improves the quality of the panels because the glue therein is at once put under pressure and there is no delay in making up a pile, as in the old process, and

a very great saving in capital and in expense of operation, a saving amounting to at least $1.50 per thousand feet of three-ply, 4; inch panels, in a plant producing 50,000 .feet of panels per day, thus saving its cost in a few months operation. 4

Referring to the drawings, in which one form of an apparatus for performing this process, is shown, the glue-spreader 1 (Fig.

l) delivers the glued sheets of veneer to the assembling table 2, where the raw plywood panels are assembled. As soon as one such raw panel is assembled, the conveyor chain 3 engages the raw panel and feeds itbetween the r first pair of driven pressure rolls 4 and 5,

hereinafter more particularly described, of the first section f the apparatus. As the front edge of this raw panel vis fed between the rolls 4 and 5, it raises the spring-pressed roller 5 a predetermined distance, say inch, and receives the amount of pressure developed by the springs when they are thus compressed an additional inch more than when adjusted without the panel thereunder, as hereinafter described. .The front edge of the raw panel is thus compressed and 5 is such that the springs of the rollers will be under greater initial compression when the upper stops thereof, hereinafter described, are screwed. down on the rods to bring the rollers 5 to the same level as those in the first section 6, and therefore they each apply a greater pressure on the panel when they are raised the same amount (-R thereby as it passes. All the rollers are driven at the same peripheral speed and in the same manner as those in the first section, above described. As the panel reaches this second section, therefore, the only difference in the action of the apparatus thereon is that the pressure of the rollers is greater than that in the first section.

A similar increase, with an otherwise iden-. tical action; is repeated in the third section 11, and again in the fourth section 12'of the apparatus.

By the time the panel has completed the length of the entire apparatus the glue thereworked in whatever wa may be desired, and does not need to be stac ed under pressure.

In order to carry out the above described process-I- have illustrated one form of the apparatus in the drawings. This consists of a series of units or sections, each identical with the others, except for its adjustment as above outlined, and placed end to end. Each comprises a frame 21 carrying the lower set of rollers 4 in suitable fixed bearings 22 therein, all said rollers 4 being driven by the chain '7. A carrier frame 23 is adjustably supported over the frame 21 by means of four or more vertical screw rods 24, each rotatably mounted in bearings 25 in the said upper frame 23 and screwing into lugs 26 extending out from fed on to the next pair of rollers, where the the lower frame 21. These rods 24 are all same degree of pressure is applied thereto.

succeeding portion of the raw panel is brought successively under the pressure of each spring-pressed roller) Also it will be noted that all the upper and lower rollers turn at exactly equal peripheral speeds, say twenty feet per minute, and in opposite rotational directions, .thus feeding the raw panel through the. first section 6 of the apparatus .at a constant speed and with substantially no strain on the glue in the panel, except that due to the compression thereof by each pair ofrollers. The said rollers 4 may be driven by a suitable drive chain 7- and the rollers 5 by another drive chain 8. Both chains 7 and 8 may be driven from any suitable driving means, such as indicated at 9.

The action of the first section 6 is repeated in the second section 10 of the apparatus,- except that in this section the adjustment of the carrier frame of the upper set of rollers connected together by means of suitable bevel gears 27 and by the horizontal shafts .28, which are *mounted in suitable bearin s 29 on the saidframe 23. Theshafts28 area apted to be turned by means of the hand wheels 30 mounted thereon; Thus by turning any of the shafts 28 all the vertical screw rods 24 of that section are rotated equallyand are screwed into or out of the supporting lugs 26 to lower or to raise the said frame 23, as deprovided with a smooth central vertical hole therethroiigh. The said vertical rod 34 asses througha guide hole in the, lower auge 32 of the frame 23 and through the above mentioned central hole in the sleeve in will have set and the panel is ready to be 35 A flange or collar 36 is formed on the rod-34 at a point slightly above the lower flange 32.

An upper stop nut 37 is adjustably screwed on the upper end of the rod 34, above the sleeve 35, and is adapted to engage the upper end ofvthe said sleeve to limit the downward motion of the rod 34 therein, thereby forming an adjustable means of controlling the position of the roller 5 when no panel is in engagement therewith. The rod 34 can move freely upward in said sleeve 35 from said lower limiting position.

A helical spring 38 is wound around the rod 34 and is compressed between the lower surface of the sleeve 35 and the collar 36 on the rod 34. This spring presses the rod 34, bearing 33, and roller 5, downward on the panel passing between the rollers. The degree of pressure exerted by the spring 38 when the roller 5 is raised inch by the passing panel, depends on the adjustment of v the frame 23 above the frame 21, on the adjustment of the sleeve 35 in the frame 23, and the adjustment of the sto nut 37 on the rod 34. When a panel of a different thickness is to, be passed through the apparatus, then the height of the frame 23, above the frame 21, and therefore the height of all the apparatus supported thereby, is altered an amount corresponding to the change in such thickness so that the pressure applied by-the rollers 5, when raised inc will not be different than in the othercase, unless a difference therein is desired. As an example of the amount of pressure exerted by the springs on the rollers 5 I may state that in the apparatus at present in successful use, each spring in the first section exerts a pressure of two pounds when raised inch by the panel; in the second section the pressure is four pounds; in the third section it is seven pounds; and in the fourthsection it is ten pounds.

The glues used in this rocess,'as above stated, must be of the quic -drying variety. When a cold Inc is desired I prefer to use one of the big protein-base vegetable glues. However if a blood-albumen glue is used it is necessary to apply heat'to the panels as they are passing through the apparatus, to promote the coagulation thereof. This heat may be obtained from a series of steam pipes 39 which may be supported in the frames 21 and 23 immediately below the rollers 4 and above the rollers 5.

In the above description I have set forth the preferred type of apparatus which I use but it is evident that other types might be develo ed, such as a progressive plate type, or a c ain carrier, without departing from the scope of my invention which, in brief, comprises the continuous conveyance of the raw panel through substantially continuous pressure conditions, each part of each panel experiencing successivel each such pressure condition, and the spee of such conveyance and the length of such pressure apparatus and the kind of glue used are coordinated such that the glue is set in the panel before thepanel reaches the end of the said pressure apparatus.

Having, therefore, described my invention, what I claim is In an apparatus for making plywood, the combination with a fixed'frame; of a vertically ad'ustable frame mounted thereon; a series of rotating feed rollers mounted in said fixed frame and adapted to feed the raw panel through the machine and to support it against the pressure therein; a series of ver tical sleeves adjustably mounted in said ad justable frame; vertically guided rods mounted in and freely moving in said sleeves; adjustable limiting nuts on the upper ends of said rods and adapted to engage the 'upper ends of said sleeves to limit the downward motion of said rods therein; compression springs mounted between, the lower ends of said sleeves and collars on said rods, Whereb the rods. are resiliently forced downward; earings mounted on the lower ends of said rods; and a series of rotating pressure rollers mounted in said bearings, each ressure roller being positioned above one 0 said feed rollers and ada ted to press the raw panel between it and said feed roller as it asses therebetween, and whereby the initia pressure of the feed roller is governed by the adjusted position of the sleeve in the frame and the limiting-nut on said rod, and whereby adjustment for the thickness of the panel without changing the pressure of the roller thereon is attained by adjusting the adjustable frame.

GEORGE HENRY O SGOOD. 

